Mix of 16mm and 25mm Meter Tails

[kevkdg]

Hi,

Just had a new Smart Meter fitted yesterday along with isolator.

The chaps installing the SMART meter used 16mm tails from the main DNO fuse cut out (containing 80 amp fuse) to the meter, but then used 25mm tails from the meter to the newly installed isolator (which they also installed). I am wondering why they didn't use 25mm from cut out to meter, if for no other purpose than constancy. Might this be due to the size of the terminals and/or entry holes for the cable in the older Henley Series 3 Bakelite Cut out which I have. They wrapped insulating tape around the tails where they enter the cut out holes just to ensure no gaps. I think the tape sits just above the cut out cable entry holes and does not extend through it.

Should I flag this?

I also asked them for an "80amp Fuse Fitted" sticker for the Cut Out for future reference but they didn't have any. Any ideas where I can get one? Have an EV charge point being installed and seem to recall they will want to know the fuse size, and it will look much better if it is labelled.

 

[Avo Mk8]

I also asked them for an "80amp Fuse Fitted" sticker for the Cut Out for future reference but they didn't have any. Any ideas where I can get one?

I noticed a photo on the UK Power Networks website showing a label seemingly made with a Brother labelling machine!
Any friends got one?

 

[DPG]

I noticed a photo on the UK Power Networks website showing a label seemingly made with a Brother labelling machine!
Any friends got one?

View attachment 94877

Glad they labelled live and neutral. Would have been tricky to know which was which otherwise

 

[kevkdg]

Good idea, I'll ask around
cheers

 

[snowhead]

If you can't get a labeller just write 80a Fuse and the date it was checked near to the Cut out

 

[kevkdg]

Label aside, any thoughts on why the SMART meter fitter used 16mm tails from cut out to meter but 25mm tails from meter to isolator? This is an 80amp supply. cheers

 

[Avo Mk8]

Label aside, any thoughts on why the SMART meter fitter used 16mm tails from cut out to meter but 25mm tails from meter to isolator? This is an 80amp supply. cheers

No personal knowledge on this, but I've read comments, I think elswhere on this forum, that this is quite common for 80A supplies to be so fitted, including the 16 to meter and 25 from meter combo.

 

[kevkdg]

I did wonder whether it was simply the logistics of getting the 25mm tails into the older style 80amp max rated Henley Series 3 cut out or possibly the terminals inside.
I mean the meter installer went to the effort of wrapping insulating tape around the 16mm tails where they enter the cut out and meter to ensure there is no gap, but the wrapped tape itself does not appear to extend into the cable entry hole in the cut out.

The old meter he removed had cable boots/grommets/guides (not sure of official name) where the tails entered the meter, but apparently they don't use these anymore and opt for insulating tape. I think people slid them down and inserted metal rods to bypass the meter. Not sure insulating tape will avoid this though lol.



As long as 16mm is OK for 80 amps then all good.

 

[Avo Mk8]

As long as 16mm is OK for 80 amps then all good.

16mm is fine for 80A

 

[kevkdg]

If I wanted the DNO to upgrade me to a 100 amp supply, I assume I would need a more up to date cut out. Does anyone know what the maximum fuse rating is for a Henley Series 3? I cannot see it printed/embossed into the bakelite anywhere.

 

[7029 dave]

Yes that cutout will only except safely 16mm tails, 25mm is too big and the risk of exposed copper showing,80A is fine with 16mm tails, see loads of this type of cutout with 60A service fuse.

 

[Andief]

New on here so be gentle. The cut outs that will only allow 16mm can be used with 25mm. its a case of stepping the insulation and the inner protection then fits through the opening and the outer protection sits flush or just inside the opening on the cut out. Thats assuming its a 100 amp fuse in the cut out. Our COP states that we can use 16mm for 60 -80 amp fuses but must be 25mm if its 100.

 

[kevkdg]

New on here so be gentle. The cut outs that will only allow 16mm can be used with 25mm. its a case of stepping the insulation and the inner protection then fits through the opening and the outer protection sits flush or just inside the opening on the cut out. Thats assuming its a 100 amp fuse in the cut out. Our COP states that we can use 16mm for 60 -80 amp fuses but must be 25mm if its 100.

Hi, in this instance my fuse is fitted is 80 amp and I think the Henley Series 3 Cut Out is only rated to a max of 80 amps too.

I guess the meter fitter was happy to leave the 16mm tails in place. It was just interesting why he went with 25mm from the meter to the isolator. I guess it is future proofed to a point that way!

 

[Andief]

Hi, in this instance my fuse is fitted is 80 amp and I think the Henley Series 3 Cut Out is only rated to a max of 80 amps too.

I guess the meter fitter was happy to leave the 16mm tails in place. It was just interesting why he went with 25mm from the meter to the isolator. I guess it is future proofed to a point that way!

Your guess is a good as mine as to the 25mm cable between the meter and isolator considering the tails to the CU look like 16mm. The future proofing would be pointless in my opinion as if you went up to 25mm on the CU tails i would think you would be upgrading to a 100 amp in the cut out and the 16mm would require an upgrade as well. Ill pose the question to some of my team and see what they say but its beyond me to be honest. 25mm is fail safe to a point bearing in mind that the main incommer is generally 16mm in most installs I deal with. re another comment about identification I wish i had shares in cable ties as we have to put them on every cable x1 on the supply x2 on every load and x3 if its off peak. I recon each install = 2 rain forest trees and a monkey !!!!

 

[SHFW74]

Your guess is a good as mine as to the 25mm cable between the meter and isolator considering the tails to the CU look like 16mm. The future proofing would be pointless in my opinion as if you went up to 25mm on the CU tails i would think you would be upgrading to a 100 amp in the cut out and the 16mm would require an upgrade as well. Ill pose the question to some of my team and see what they say but its beyond me to be honest. 25mm is fail safe to a point bearing in mind that the main incommer is generally 16mm in most installs I deal with. re another comment about identification I wish i had shares in cable ties as we have to put them on every cable x1 on the supply x2 on every load and x3 if its off peak. I recon each install = 2 rain forest trees and a monkey !!!!

I am having UKPN move fuse and meter to outside wall but been told that as the Distribution Board is still in the under stair cupboard in the middle of the house, I would need to run an armoured cable from the isolator in the meter box to the distribution Board. The fuse is going to be upgraded from 80A to 100A and the armoured cable will need to be about 15m point to point. Will 25mm 3 core SWA be adequate for the the cable or should we be looking at fitting 35mm 3 core SWA over that distance?

 

[R-fur]

I am having UKPN move fuse and meter to outside wall but been told that as the Distribution Board is still in the under stair cupboard in the middle of the house, I would need to run an armoured cable from the isolator in the meter box to the distribution Board. The fuse is going to be upgraded from 80A to 100A and the armoured cable will need to be about 15m point to point. Will 25mm 3 core SWA be adequate for the the cable or should we be looking at fitting 35mm 3 core SWA over that distance?

25mm will be fine but you will also need a switch fuse within three meters of the Meter.

 

[SHFW74]

25mm will be fine but you will also need a switch fuse within three meters of the Meter.

Thanks. UKPN are fitting new fuse in meter cupboard with meter. The isolator switchbwill be fitted in meter cupboard between the meter and SWA cable. Are you saying I also need an additional switched fuse between the meter and the isolator as UKPN didn’t mention this